This invention relates generally to braking systems and more particularly to braking systems for in-line roller skates.
In-line roller skates employ at least two wheels positioned to rotate within a common, vertical plane. In-line roller skates are operated in a manner similar to that employed to operate ice skates, requiring substantially the same bodily movements to initiate and sustain forward motion. In-line roller skates are suitable for use in designated roller skating facilities and for on-street operation. This type of skate has become increasingly popular for fitness, recreational, and competitive skating. U.S. Pat. No. 5,028,058 (1990) to B. J. Olson typifies the characteristics of currently available in-line roller skates.
Currently available in-line roller skates enable skaters to achieve high skating speeds, particularly when skating outdoors on hilly terrain. In-line roller skate brakes which develop substantial braking forces are required for safe operation under such conditions. Currently available brakes are not adequate for all potentially-safe skating conditions, and can limit the skater to operation on level or semi-level surfaces.
Currently available in-line roller skates typically employ a brake assembly which is rigidly attached to or integral with the rear of the skate behind the skate rear wheel. The skater applies the brake by extending the skate slightly forward and lifting the forward end of the skate pivotally about the rear wheel. This brings a ground-engaging rubber brake pad into contact with the skating surface, and the resulting friction force slows or stops the forward motion of the skater. U.S. Pat. No. 5,028,058 also typifies the characteristics of this type of brake on currently available in-line roller skates. U.S. Pat. Nos. 4,298,209 to J. Peters (1981) and 2,872,201 to B. T. Wagers (1955) show this type of brake employed on tandem roller skates. Currently available in-line roller skate brakes such as the brake by Olson have several shortcomings:
a) The stopping force which the skater can generate is limited in magnitude. Persons of average skating ability can generally skate safely only on level or semi-level surfaces due to braking limitations. PA0 b) The brake pad exhibits excessive wear when operated on asphalt, sidewalk-finished concrete, or other abrasive, non-slip surfaces. The majority of outdoor skating surfaces are of this type. As a result, frequent outdoor skating generally leads to frequent brake pad replacement. PA0 c) Slightly irregular or mildly bumpy surfaces are often encountered in outdoor skating. Upon initial brake application on these types of surfaces the brake pad often skips or vibrates on the skating surface. The rigid nature of the brake mounting to the skate transfers these braking induced vibrations directly to the skate. This makes brake application difficult.
Another type of roller skate brake which can provide large-magnitude stopping forces is typified by U.S. Pat. Nos. 4,807,893 to C. H. Huang (1989); 2,027,487 to W. H. Means (1936); and 218,035 to J. S. Lash (1879). These brakes are shown implemented on tandem roller skates. A brake pad or roller is located behind the rear wheels of the skate, and is attached to the skate by a lever arrangement. The skater applies the brake by extending the skate slightly forward and lifting the forward end of the skate pivotally about the rear wheel. This brings the brake pad or roller into contact with the skating surface, and actuates one end of the lever arrangement. A second brake pad on the opposite end of the lever arrangement is pressed into contact with the rear skate wheels. This slows wheel rotation, thereby slowing the forward motion of the skater. These brakes can produce large-magnitude braking forces, but have a severe shortcoming when considered for application on current in-line roller skates because current in-line roller skates employ wheels made of resilient, rubber-like materials. Wheels of this type will wear excessively if pressed into sliding contact with a brake pad as discussed above. These wheels are also relatively expensive. Brake-induced wear on the skate wheels will result in expensive, premature wheel replacement.
A second type of prior-art roller skate brake employs a roller or rollers which press into the skate wheels upon brake application. The rolling resistance created between the wheel and roller slows wheel rotation, thereby slowing the forward motion of the skater. Examples of this type of brake are shown in U.S. Pat. Nos. 4,312,514 to I. Horowitz (1982); 3,224,785 to G. W. Stevenson (1965); and 920,848 to R. B. Eubank (1909). The brakes in these patents have not enjoyed widespread use, however.
The roller-brake in U.S. Pat. No. 4,312,514 is not suitable for intermittent braking purposes. This brake develops braking forces in a continuous manner, and is intended to be a speed-limiting device for beginning skaters. The braking force is safely adjusted only when the skater is completely stopped.
The roller-brake embodiments in U.S. Pat. No. 3,224,785 are either too complex to be practical, or would induce excessive wear on the rear skate wheel if employed on current in-line roller skates. Brake operation produces roller-wheel slippage, and this would cause excessive wear on the rear wheel.
The roller-brake in U.S. Pat. No. 920,848 is arranged in an awkward manner for current skating practices. Normal forward-propelling bodily movements could easily lead to unintentional brake application, particularly when skating uphill.
The brakes U.S. Pat. Nos. 4,312,514 and 920,848 depend upon rolling resistance generated by contact between the skate rear wheels and associated rollers to generate braking forces. Roller-wheel rolling resistance will produce braking forces adequate for in-line roller skates only if excessive normal forces between the wheel and roller are developed. Such large forces tend to be damaging to the skate wheel and other parts of the skate.
Other relevant prior-art for roller-brakes appears in U.S. Pat. Nos. 650,228 to G. Cattaneo (1900); 616,429 to W. H. Sparks (1898); 559,294 to L. C. Lambert (1896); 540,637 to F. J. Cole (1895); and 508,832 to S. E. Odell (1893). The brakes in these patents are designed for wagons and bicycles and are not practical for in-line roller skates.